Bis 1, 1 isocyanatoalkyl cycloalkanes

ABSTRACT

Alkyl diisocyanates such as 1-(isocyanatomethyl)-1-(3isocyanatopropyl) cyclohexane; 1-(isocyanatomethyl)-1-(3isocyanatoethyl) cyclohexane; bicyclo-(2.2.1)-2-isocyanatoethyl2-(3-isocyanatopropyl)-heptane; bicyclo (4.3.0)-2isocyanatomethyl-2-(3-isocyanatopropyl)-nonane and polyurethanes prepared therefrom. The diisocyanates are prepared by reacting the corresponding diamines with phosgene.

[Jnited States Patent [72] Inventors Julian Feldman;

Robert ,1. Shaw, both of Cincinnati, Ohio [21] App1.N0. 694,114 [22]Filed Dec. 28, 1967 [45] Patented Dec. 7, 1971 [73] Assignee NationalDistillers and Chemlcai Corporation New York, N.1(.

[54] MS 1, 1 ISOCYANATOALKYL CYCLOALKANES 5 (Ilnlms, No Drawings [52]1.1.8. C1 260/453 A, 260/2.5 AT, 260/77.5 AM, 260/77.5 AT, 260/345.2,260/153 PH, 260/464, 260/465.8, 260/544 C, 260/563 C, 260/563 P, 260/563R [51] 1nt.Cl C07c 1119/04, C08g 22/24, C08g 22/44 [50] Field of Search260/453 A [56] References Cited UNITED STATES PATENTS 2,319,057 5/1943Hanford 260/453 2,824,858 2/1958 Melamed 260/453 X 2,865,940 12/1958Nobis et a1 260/453 Siefl enz Annalen der Chemic, Vol. 562, p. 124(1949). Schipper: Chemical Abstracts, Vol. 56, p. 11466 1962).

Primary Examiner-Charles B. Parker Assistant Examiner-Dolph 1'1.Torrence Attorney-Allen A. Meyer, Jr.

ABSTRACT: Alkyl diisocyanates such asl-(isocyanatomethy1)-l-(3-isocyanatopropy1) cyclohexane;l-(isocyanatomethyl)-1-(3-isocyanatoethyl) cyclohexane; bicyclo-[2.2.1]-2-isocyanatoethy1-2-(3-isocyanatopropyl)-heptane; bicyclo[413.0]-2-is0cyanatomethy1-2-(3-isocyanatopr0pyl) nonane andpolyurethanes prepared therefrom. The diisocyanates are prepared byreacting the corresponding diamines with phosgene.

MS I, l HSOCYANATOALKYIL CYCLOAMMNES This invention relates to alkyldiisocyanates in which the 2- carbon on the alkyl chain is part of acycloaliphatic ring, to a process for preparing such diisocyanates, topolyurethanes prepared employing such diisocyanates, and to a processfor 5 producing such polyurethanes.

Polyurethanes are polymers of glycols with aliphatic or aromaticdiisocyanates. For example, Perlon U polyurethane is the polymer oftetramethylene glycol and hexamethylene diisocyanate, according to theequation: 7 10 The lower aliphatic diisocyanates that are normally usedin making polyurethanes are relatively volatile compounds and theirvapors have a high toxicity which makes handling these compounds ratherhazardous. Aromatic diisocyanates can be employed in place of aliphaticdiisocyanates. However, the polyurethanes prepared by reacting aromaticdiisocyanates with glycols tend to discolor rapidly, more so than wherealiphatic diisocyanates are employed. The cycloaliphatic diisocyanatesof the instant invention have been found to be especially useful in thepreparation of polyurethanes inasmuch as the cycloaliphaticdiisocyanates are less volatile and therefore less hazardous then thealiphatic diisocyanates employed heretofore. Furthermore, thepolyurethanes produced by reacting the cycloaliphatic diisocyanates withglycols in accordance with conventional polyurethane preparatoryprocedures discolor at a much slower rate than do those producedemploying aromatic diisocyanates.

The invention provides a process for preparing high molecular weightalkyl diisocyanates in which the 2-carbon atom on the alkyl chain ispart of a cycloaliphatic ring, from low molecular weight dinitriles,which comprises reacting a 2- methylene aliphatic dinitrile with a1,3-diene or a l,3-cycloalkadiene in the Diels-Alder reaction to form aring-unsaturated cycloaliphatic dinitrile wherein one of the two nitrilegroups is attached via an alkyl group to the same ring carbon atom asthe other nitrile group, reducing the ring-unsaturated cycloaliphaticdinitrile to the corresponding ring-saturated cycloaliphatic diamine,and reacting the ring-saturated cycloaliph'atic diamine or a saltthereof with phosgene to form the alkyl diisocyanates.

By the process of the invention, it is now possible to prepare alkyldiisocyanates of a complicated structure, having a higher molecularweight than the aliphatic diisocyanates heretofore employed in makingpolyurethanes, and which are difficult of access by other routes,starting with simple starting materials that are readily available, suchas 1,3-dienes, and Z-methylene glutaronitrile and itacononitrile, whichare also readily prepared by conventional processes. In these alkyldiisocyanates, the Z-carbon atom in the alkyl chain is a ring carbon ina cycloaliphatic ring with the alkyl isocyanate groups attached thereto,one of which is a methyl isocyanate group and the other an alkylisocyanate group having two or three carbon atoms in the alkyl chain.The cycloaliphatic group can be a cyclohexane ring or a bicyclo ortricyclo ring in which the endo carbon atom can have none or a varietyof alkyl substituents.

The alkyl diisocyanates in accordance with the instant invention areaccordingly encompassed by the following formula:

The bicycloand tricycloalkane alkyl diisocyanates are defined asfollows:

In the above formulas, X and Y can be the same or different, and areselected from the group consisting of hydrogen, halogen, alkyl havingfrom about one to about 12 carbon atoms, alkylene having from about oneto about 12 carbon atoms, alkoxy having from about one to about eightcarbon atoms, and aryl having from about six to about 12 carbon atoms;

n is the integer l or 2,

n is an integer ranging from zero to about three and Y is present onlywhen n is zero. When n is zero, the ring is cyclohexane, and when n isone to three, the ring is a bicycloalkane ring.

Preferably, n is two, n is zero, and X and Y are hydrogen.

The X groups on adjacent carbon atoms in formulas l, [I and II] can beinterconnected by hydrocarbon, ether or ester bridges to form a varietyof cycloaliphatic and heterocyclic ring compounds. Thus, for example,two X groups can be taken together as an alkyl group having from aboutthree to about six carbon atoms, thereby forming a second or thirdcycloaliphatic ring as in indane or tetralin, or as an oxyalkyl grouphaving from about two to about five carbon atoms and one or two etheroxygens, thereby forming an oxygen-containing heterocyclic ring or anester group having from about three to about six carbon atoms, therebyforming a lactone ring. Thus, for example, a five-memberedoxyheterocyclic ring can have one oxygen atom, a six-memberedoxyheterocyclic ring can have two oxygen atoms and a sevenoreight-member ed oxyheterocyclic ring can have three oxygen atoms.

Typical alkyl groups include methyl, ethyl, propyl, isopropyl, n-butyl,isobutyl, tertiary butyl, secondary butyl, amyl, hexyl, isoamyl,isohcxyl, tertiary hexyl, heptyl, isoheptyl, n-octyl, 2-ethylhexyl,isooctyl, nonyl, decyl, undecyl, and dodecyl.

Typical alkoxy groups include methoxy, ethoxy, butoxy, propoxy, amyloxy,hexoxy, heptoxy, octoxy, and decyloxy.

Typical alkylene groups include methylene, ethylene, 1,3- propylene,1,2-propylene, 1,2-butylene, 1,3-butylene, 1,4-butylene, and likeamylene, hexylene, heptylene, octylene and decylene radicals.

The halogen can be fluorine, bromine, chlorine, or iodine.

Typical aryl groups include phenyl, p-tolyl, o-tolyl, p-xylyl, andnaphthyl.

Examples of l,l-diisocyanato alkyl cyclohexane in accordance with theinvention include, but are not limited to, l-(isocyanatomethyl)-I-(B-isocyanatopropyl) cyclohexane; l-(isocyanatomethyl)-l-(2-isocyanatoethyl) cyclohexane; l-(isocyanatomethyl l 3-isocyanatopropyl )-4-methylcyclohexane,l-(isocyanatomethyl)- l 3-isocyanatopropyl)-2,3,4,5,-tetrachlorocyclohexane; and similar 3-methyl compounds.

Examples of 2,2-diisocyanato alkyl bicycloalkanes in accordance with theinvention as represented by formulas l and Ill include, but are notlimited to, bicyclo[ 2.2. l 2-isocyanatomethyl-2- 34socyanatopropylheptane; bicyclo[2.2. 1 ]-2-isocyanatomethyl-2- 3-isocyanatopropyl)-tricyclo[2.2.1.3"]-2-isocyanatomethyl-2-(3-isocyanatopropyl )-decane;

3-oxabicyclo[ 3.4.0]-8-isocyanatomethyl-8-( 3-isocyanatopropyl )-nonane;and

3-oxatricyclo[3.4.0. l "']-8-isocyanatopmethyl-8-( 3-isocyanatopropyl)-decane.

Preparation of Ring-Unsaturated Cycloaliphatic Dinitriles In the processof the invention for preparing the alkyl diisocyanates, the 1,3-diene isreacted with the 2-methylene aliphatic dinitrile to produce aring-unsaturated cycloaliphatic dinitrile in a Diels-Alder condensationsuch as that described in copending application Ser. No. 617,042, filedFeb. 20, 1967 according to the following equation:

wherein X, Y, and n and n are as defined hereinbefore.

The 2-methy1ene aliphatic dinitriles employed are defined by theformula:

CH2 NC[CH2]n,( 3CN wherein n is as defined hereinbefore, and the totalnumber of carbon atoms in the dinitrile is five or six. Exemplary of thealiphatic dinitriles falling within the above class are 2- methyleneglutaronitrile and itaconodinitrile.

The Z-methylene aliphatic dinitriles of the invention are knowncompounds, and are 'obtained using known procedures. Such procedures aredescribed, for example, in French Pat. No. 138,844, Belgian Pat. No.677,175, Belgian Pat. No. 677,265, French Pat. No. 1,41 1,003, BritishPat. No. l,0l8,220, and Journal of Organic Chemistry 30 1357-60 (1965).ltaconitrile may be prepared from itaconic acid by known methods.

The 1,3-diene has the general formula wherein X, Y, and n are as definedhereinbefore. Y is present only when n is zero. Typical 1,3-dienessuitable for use in preparing the ring unsaturated cycloaliphaticdinitriles include butadiene, 2,3-dimethyl butadiene, B-n-propylhexadiene, isoprene, piperylene cyclopentadiene,hexachlorocyelopentadiene, hexachlorobutadiene, a-vinyl-naphthalene,anthracene, chloroprene, 2-methoxybutadiene, fulvene, anddicyclopentadiene.

In the Diels-Alder condensation for preparing the ring-unsaturatedcycloaliphatic dinitrile starting material, the 2- methylene aliphaticdinitrile is reacted with the l,3-diene in a molar ratio of thedinitrile compound to the diene within the range from about 0.8:1 toabout 1.2:1, and preferably ltl. A large excess of either reactant canlead to the formation of undesirable byproducts and thus should beavoided. The reaction can be carried out in the presence of an inertsolvent or reaction medium, such as, for example, toluene, xylene,nitrobenzene, benzonitrile, and carbon tetrachloride. However, a solventneed only be employed if the Z-methylene aliphatic dinitrile and the1,3-diene reactants are immiscible under reaction conditions.

In the Diels-Alder reaction of the 2-methylene aliphatic dinitrile withthe 1,3-diene, the temperature of the reaction is maintained within therange from about 50 to about 200 C., and preferably from 1 10 to aboutC. The reaction time should be within a range from about 0.25 to about30 hours, and preferably from about 5 to about 15 hours. The desiredproduct may be recovered from the resulting reaction product mixture byconventional procedures such as distillation and/or crystallization.

Preparation of Ring-Saturated cycloaliphatic Diamines Thering-unsaturated cycloaliphatic dinitriles are reduced to thecorresponding ring-saturated cycloaliphatic di(aminoalkanes) byhydrogenating the ring-unsaturated cycloaliphatic dinitriles preferablyin accordance with a two-step procedure described in application, Ser.No. 694,073, entitled Cycloaliphatic Di(aminoalkanes and Process forProducing the Same filed concurrently herewith.

The hydrogenation of the ring-unsaturated cycloaliphatic dinitrile maybe represented by the following equation:

"'riie' reduction of B3 nitrile groups a nd of the ring double bond ispreferably carried out stepwise with the reduction of the nitrile groupsas the first step. The first step preferably involves the hydrogenationof the nitrile groups in the presence of ammonia and a suitable catalystsuch as cobalt or nickel. The second step preferably involves reductionof the ring double bond by hydronation in the presence of a suitablecatalyst such as palladium or platinum. It is preferred to employ astepwise procedure since complete reduction of the ring double bond isnot obtained in a single step procedure. Reduction of Preparation of theDiisocyanates from the Diamines The ring-saturated cycloaliphaticdiamines can be converted to the corresponding diisocyanates of theinvention by reacting the diamine, or a salt thereof, with phosgene inaccordance with the following equation;

112N032 [om n oamm wherein X, Y, n and 11 are defined as hereinbefore.

The diisocyanate is formed by reaction with phosgene in excess of theamount stoichiometrically required, usually from about 2.2 to about 4moles per mole of cycloaliphatic diamine. Two moles of phosgene reactwith each mole of the diamine to form the diisocyanate.

When the free cycloaliphatic diamine is employed, the initial stage ofthe reaction is carried out at a temperature below room temperature, andpreferably at from about to about 5 C. External cooling can be applied,and an excess of phosgene is employed in this initial stage.

The initial stage in the reaction is the formation of the carbamylchloride and amine hydrochloride, but this product is not isolated. Itis converted to the diisocyanate by liberation of the hydrogen chloride,in the second stage of the reaction, which is carried out at an elevatedtemperature.

During the second stage, the reaction mixture is kept under a flow ofexcess phosgene in order to drive the reaction to completion. Theconversion is effected at a temperature within the range from bout 125to about 190 C., and preferably at from about 150 to about 180 C. Thereaction is continued until liberation of hydrogen chloride has ceased.This may require from 3 up to about hours, depending upon thetemperature and the structure of the diamine and diisocyanate.

1f the acid salt of the cyloaliphatic amine is employed, it isunnecessary to carry out the reaction at low temperature. instead, thereaction mixture can be heated at once under a flow of phosgene, andheating continued until liberation of hydrogen chloride has ceased, asbefore.

The reaction can be carried out in the presence of an inert solvent.Exemplary are aromatic hydrocarbons, such as toluene and xylene,nitrobenzene, nitriles, such as benzonitrile and chlorinatedhydrocarbons, such as carbon tetrachloride and orthodichlorobenzene.

The cycloaliphatic diamine salts can, for example, be the hydrochloride,hydrobromide, and carbamate salts. These can be prepared from the aminesby reaction with the corresponding acid and with carbon dioxide.

After completion of the reaction, the alkyl diisocyanate can berecovered by distillation of the solvent, if any, and phosgene, followedby distillation of the diisocyanate under reduced pressure, so as tokeep the distillation temperature at below the decomposition temperatureof the diisocyanate.

The diisocyanate can then be employed in the preparation ofpolyurethanes, polyamides, or diisocyanate-modified polyesters, as willbe discussed following the working examples.

In preparing the alkyl diisocyanates of the invention, starting from the1,3-diene or 1,3-cycloalkadiene and the 2- methylene aliphaticdinitrile, the above-described operational steps can be carried outbatchwise, in sequence, or in the form of a continuous operation, inwhich the reaction mixture from one step is processed so as to recoverthe desired reaction products, separating any unreacted materials andrecycling them to the start of that step, and then passed to the nextstep. In a commercial operation, a continuous system is preferred.

The following examples in the opinion of the inventors representpreferred embodiments of their invention. The ringsaturatedcycloaliphatic diamines used as starting materials in the followingexamples were prepared in accordance with the procedure described in theaforementioned copending application, Ser. No. 694,073 entitledcycloaliphatic Di(aminoalkanes) and Process for Producing the Same"tiled concurrently herewith.

About 25 g. of l-(aminomethyl)-l-(3-aminopropy1)- cyclohexane weredissolved in about 75 ml. of methanol in a reactor and anhydroushydrogen chloride was bubbled into the solution for about 2.5 hourswhile the solution was maintained at a temperature within a range fromabout 20 to 25 C. by means of a cooling bath. The hydrogen chloride wasadded until somewhat more than the theoretically required weight hadbeen added for formation of the dihydrochloride. No solid precipitatedduring the addition. About 35.6 g. of the solid hydrochloride wereisolated by distilling off the methanol. The final traces of methanolwere removed by azeotropic distillation with benzene.

About 30.4 g. (0.125 mole) of the dihydrochloride were introduced into areactor comprising a 500 ml. flask equipped with a gas-inlet tube,stirrer, reflux condenser and thermometer along with ml. ofo-dichlorobenzene. The contents of the flask were heated at about 155 C.during which time phosgene at a rate of 60 cc./min. was introduced. Thereaction was continued for about 8 hours. At the end of this period, theflow of phosgene was discontinued and the flask was purged with nitrogengas for about 15 minutes. The solution was cooled and was the subjectedto fractional distillation under vacuum. The solvent was removed at 10mm. of Hg pressure and the residue was distilled at 0.3 mm. of Hg. Al-(isocyanatomethyl)-l-(3-isocyanatopropyl) cyclohexane product wasobtained as a colorless liquid boiling at 1 18 C. at 0.3 mm. Hg.

Analysis of the product by titration with dibutylamine showed that theproduct was 98.3 percent pure. The structure of the product wasconfirmed to be that of l-(isocyanatomethy1)-1-(3-isocyanatopropyl)cyclohexane by mass spectroscopy, by infrared analysis and by nuclearmagnetic resonance. An analysis of the product for carbon, hydrogen andnitrogen gave the following results:

Found Theoretical '16 carbon 65.05-64.96 64.82 )i\ hydrogen 8.12-8.068.16 nitrogen 12.57-12.60 12.60

1-( isocyanatomethyl)- l 3-isocyanartopropyl) cyclohexane has a vaporpressure of 0.3 mm. Hg at 1 18 C. and is substantially less volatilethan known aromatic and aliphatic diisocyanates employed in themanufacture of polyurethanes and thus is substantially less hazardous tohandle EXAMPLE 2 About 40 g. of the l-(aminomethyl)-I-(3-aminopropyl)-4-ethyl-5-n-propyl-cyclohexane are dissolved in about ml. of benzene andanhydrous hydrogen chloride is bubbled into the solution for about 2hours while the solution is maintained at a temperature within a rangefrom about 20 to about 25 C. by means of a cooling bath. The hydrogenchloride is added until somewhat more than the theoretically requiredweight has been added for formation of the dihydrochloride. About 52.1g. of the solid hydrochloride are isolated by filtering of the resultingprecipitate, washing with benzene and drying under vacuum at 50 C.

About 39.2 g. (0.125 mole) of the dihydrochloride are introduced into a500 ml. flask equipped with a gas-inlet tube stirrer, reflux condenserand thermometer along with 125 ml. of o-dichlorobenzene. The contents ofthe flask are heated at about 165 C. during which time phosgene at arate of 60 cc./min. is introduced. The reaction is continued for about 8hours. At the end of this period, the flow of phosgene is discontinuedand the flask is purged with nitrogen gas for about 15 minutes. Thesolution is cooled and subjected to fractional distillation undervacuum. The solvent is removed at mm. of Hg. pressure and the residue isdistilled at 0.1 mm. of Hg. Al-(isocyanatomethyl)-1-(3-isocyanatopropyl)-4-ethyl-5-n-propyl-cyclohexane product is obtained as a colorlessliquid.

EXAMPLE 3 About 30 g. of the bicyclo[2.2.1.]-2-(aminomethyl)-2-(3-aminopropyl)heptane are dissolved in about 150 ml. of benzene andanhydrous hydrogen chloride is bubbled into the solution for about 2hours while the solution is maintained at a temperature within a rangefrom about 20 to 25 C. by means of a cooling bath. The hydrogen chlorideis added until somewhat more than the theoretically required weight hasbeen added for formation of the dihydrochloride. About 42 g. of thesolid hydrochloride are isolated by filtering off the resultingprecipitate and washing with benzene.

About 31.9 g. (0.125 mole) of the dihydrochloride are introduced into a500 ml. flask equipped with a gas-inlet tube, stirrer, reflux condenserand thermometer along with 125 ml. of odichlorobenzene. The contents ofthe flask are heated at about 165 C. during which time phosgene at arate of 60 cc./min. is introduced. The reaction is continued for about 9hours. At the end of this period, the flow of phosgene is discontinuedand the flask is purged with nitrogen gas for about minutes. Thesolution is cooled and then subjected to fractional distillation undervacuum. The solvent is removed at 10 mm. of Hg pressure and the residueis distilled at 0.1 mm. of Hg.Bicyclo[2.2.l.]-2-(isocyanatomethyl)-2-(3-isocyanatopropyl)heptane isobtained.

The alkylene diisocyanates of the invention can be employed to producepolyurethanes which are useful as foams, for example, for cushions andmattresses, and as a buoyant material. Such polyurethanes arecharacterized by having urethane groups separated by aliphatic,aromatic, mixed aliphatic-aromatic, or heterocyclic glycol unitscontaining from two to about 12 carbon atoms and wherein the urethanegroups contain high molecular weight groups in the side chain, namelythe cycloaliphatic group of the diisocyanates, which impart to thepolyurethanes a more hydrocarbon character than present in prior artpolyurethanes and some of the properties of polyolefins, such aspolyethylene and polypropylene.

Polyurethanes are prepared by reacting polyethers or aliphatic oraromatic glycols with polyisocyanates. The glycols customarily have arelatively low molecular weight, as compared to the resultingpolyurethanes, and an aliphatic, aromatic or heterocyclic structure towhich the hydroxyl groups are attached. The glycols normally areemu-glycols, i.e the hydroxyl groups normally are at the ends of thealiphatic, aromatic or heterocyclic nucleus, and the nucleus, such asthe aliphatic chain, can range up to about 12 carbon atoms, startingwith ethylene glycol. The cyclic glycols can have two hydroxyl groupsattached to the same ring, or to diflerent rings themselves connected bya suitable linking group.

The polyisocyanate is also of low molecular weight, and is adiisocyanate in accordance with the invention.

The resulting polymers contain urethane groups derived from therelatively short-chain glycol and the original isocyanate. The urethanegroups form an integral part of the polymeric chain, the properties ofwhich to a large extent are determined by the relatively short glycoland long diisocyanate units. There is accordingly a high proportion ofurethane groups per unit of molecular weight of the repeating groups inthe chain. Expressed another way, the polyurethanes of this type willnormally have one urethane group for each 12 or more carbon atoms.

The reaction of the alkyl diisocyanates of the invention with glycolsproceeds in accordance with the following equation to producepolyurethanes containing the following structure wherein p is an integerwithin the range from two to about 1,000 or more and wherein Q is analkyl or alicyclic or aryl or a mixed alkyl-arylcyclic or alkyl-arylgroup, having a straight or branched chain, containing from two to about12 carbon atoms. Typical Q groups are The aliphatic glycols suitable foruse in reacting with the 1 alkyl diisocyanates of the invention includealkylene glycols such as ethylene glycol, 12- and 1,3-propylene glycols,neopentyl glycol, butylene glycol -1,4; -1,3; and -1,2; pentanediol-l,5; -l,4; -1,3 and -1,2; hexanediols, decanediols, dodecanediols, andthe like.

Other examples of glycols include phenylene glycols, dimethylenephenylene glycols, cyclohexylene glycols, and cyclopentylene glycols.

The polyurethanes are formed by heating the glycol with an isocyanatefor several hours, at a temperature at which the reaction proceeds,usually about 1 to 3 hours, at from about 75 C. to about C. withoccasional agitation, and then continuing the reaction for an additionaltime, from 4 up to about 14 hours, at a higher temperature, usually fromabout 125 C. to about 175 C. The upper limit of reaction temperature isnot critical, and is limited only by the decomposition temperature ofthe glycol and the isocyanate.

If desired, a polyurethane catalyst may be used to increase the rate ofreaction. Any of the known urethane catalysts can be employed. Suchcatalysts include the tertiary amines, such as N-methylmorpholine,pyridine, dialkyl aniline, dimethyl ethanolamine, triethylamine, andN,N' -diethyl cyclohex' ylamine, and metal organic compounds such as thepolyvalent metal salts of organic acids, such as cobalt naphthenate andthe acetyl acetonates such as ferric acetyl acetonate, and alkyl tincompounds, such as di-nitrityl-tin diacetate, di-n-butyl tin dilaurate,and tin octoate.

Catalytic amounts of these materials are sufiicient. The amount dependsupon the activity of the catalyst, as those skilled in the art areaware. Generally from about 0.0001 to about 1 percent catalyst by weightof the isocyanate yield good results. The upper limit is established bythe rate of reaction.

The initial product of this reaction will generally be a thermoplasticpolyurethane having properties both of urethanes and of thecycloaliphatic group of the diisocyanates.

if a strong, heat-resistant, substantially insoluble material isdesired, the polyurethane can be cross-linked. The cross-linking iseffected by the methods known to the art for cross-linkingpolyurethanes. For example, an excess amount of a diisocyanate can beemployed, more diisocyanate than is theoretically required to react withall of the hydroxyl groups present in the glycol. Upon heating thismaterial, after formation of the urethane, for several hours, usuallyfrom about 8 to about 20 hours, in the presence of water, which may bein the form of water added directly to the reaction medium or in theform of atmospheric moisture, a further reaction will take place betweenthe urethane groups, and the excess diisocyanate present, converting theurethane groups to allophanate groups, thus producing a cross-linkedstructure. The additional diisocyanate molecules serve as crosslinks orbridges between polymer chains. The degree of cross-linking may becontrolled by the amount of excess diisocyanate employed. A completelycross-linked material requires at least one extra molecule ofdiisocyanate for every two urethane groups present.

If desired, other types of cross-linking agents may be employed. Forexample, the aromatic diamines and, in some cases, the aliphaticdiamines and ditertiary peroxides may also be employed. Representativeof this type of curing agent are dichlorobenzidine and p,p-diaminodiphenylmethane. Additional details of the use of such diaminecross-linking agents may be found in U.S. Pat. No. 2,620,516 to Muller.

When diamine curing agents are employed, the amount of diisocyanateemployed should more closely approximate that which is theoreticallyrequired to react with the OH groups present in the glycol. There shouldnot be more than about 100 percent excess diisocyanate per mole beyondthat required to react with all of the OH groups present in the reactionmedium. If more isocyanate is present, the reaction between freeisocyanate and diamine will often take precedence over the reactionbetween urethane and diamine, thereby preventing diamine cross-linking.When less isocyanate is employed, there will be incompletecross-linking, which, for certain use, may be desirable. The use of lessdiamine may be desirable, if less cross-linking is desired. The reactionbetween urethane groups and amine groups gives rise to a substitutedurea linkage. Additional reaction may convert the urea linkage to abiuret linkage.

The cross-linked product will vary, depending upon the originalmolecular weight of the glycol and the diisocyanate, from an insolublewaxlike material to an insoluble elastomeric material to a hard, rigid,plastic material. If it is desired to form a thread out of thismaterial, the thermoplastic reaction product of the glycol with thediisocyanate may be extruded through a conventional thread extruder andthereafter passed through a hot bath of a curing agent, such as diamine,to yield an infusible, insoluble cross-linked elastomeric thread havingexcellent physical properties for use in making bathing suits,foundation garments and the like.

Where desired, various fillers may be added to the reaction product ofthis invention, such as carbon black, silica, colorants and othermiscellaneous materials. These fillers may be added in accordance withconventional rubber and plastic technology, as for example, on atwo-roll rubber mill or a Banbury mixer.

The following examples in the opinion of the inventors representpreferred embodiments of polyurethanes of the invention.

EXAMPLE 4 About 5 g. of 1-( isocyanatomethyl l 3-isocyanatopropyl)-cyclohexane of example I, 20 ml. of dry pyridine catalystand 16 g. of polyoxypropylene glycol, molecular weight of 400-2000, arestirred together and slowly heated to C. in a polymerization reactor,and thereafter heated at C. for an additional 9 hours. A pinkish clearplastic material is produced, which is molded in a press at about C. toproduce a clear flexible film. Further heating of this film at l60-l70C. in the presence of atmospheric moisture for 20 hours produces aninfusible, xyleneand dimethylformamide insoluble material.

EXAMPLE 5 About 5 g. of l-( isocyanatomethyl l3-isocyanatopropyl)--etll\yl-S-n-propyl-cyclohexane of example 2, 20 ml.of dry pyridine and 16 g. of polyoxypropylene sorbitol, molecular weightof 700, are stirred together and slowly heated to 140 C. and thereafterheated at 145 C. for an additional 9 hours. A pinkish clear plasticmaterial is produced, which is molded in a press at about 150 C. toproduce a clear flexible film. Further heating ofthis film at l60170 C.in the presence of atmospheric moisture for 20 hours produces aninfusible, xyleneand dimethylformamide-insoluble material.

EXAMPLE 6 About 5 g. ofbicyclo[2.2.l]-2-isocyanatomethyl-2-(3-isocyanatopropyl) heptane ofexample 3 20 ml. of dry pyridine and 16 g. of polyoxypropylene gloycollare stirred together and slowly heated to 140 C., and thereafter heatedat 145 C. for an additional 9 hours. A pinkish clear plastic material isproduced, which is molded in a press at about 150 C. to produce a clearflexible film. Further heating of this film at l60-l70 C. in thepresence of atmospheric moisture for 20 hours produces an infusible,xyleneand dimethylformamideinsoluble material.

The diisocyanates of the invention can also be reacted with carboxylicacids to produce polyamides or with polyesters to producediisocyanate-modified polyesters. Thus, for example, bicycloalkanediisocyanates of the invention can be reacted with glycol-adipic acidpolyesters to lenghthen the polyester chains and this product can becross-linked by reaction with water, glycols, diamines, or aminealcohols, employing conventional techniques, as described in Polyesrersand their Applications, Ejorksten et al., (Reinhold 1960), pp. 225 to228. The diisocyanate-modified polyesters are elastomers and haveapplication as a rubber substitute as tires, conveyors and drivingbelts, shoe heels and soles and related products. in addition, they canbe foamed by conventional techniques and used as such. Furtherapplications for diisocyanate-modified polyesters are as adhesives, forexample, for bonding wood, molding compounds, surface coatings, forexample, in can coatings and in protective coatings for magnesium, ironand zinc, nonvolatile plasticizers in polyvinyl chloride, as describedin Polyesters and their Applications, supra.

Having regard to the foregoing disclosure, the following is claimed asthe inventive and patentable embodiments thereof:

11. Diisocyanates of the formula wherein X and Y- fro rn t he groupconsisting of hydrogen, halogen and alkyl having from one to six carbon

2. Diisocyanates as described in claim 1 wherein n2 is zero and X and Yare selected from the group consisting of hydrogen and alkyl having fromone to six carbon atoms. 3.1-(isocyanatomethyl)-1-(3-isocyanatopropyl)-cyclohexane. 4.1-(isocyanatomethyl)-1-(3-isocyanotopropyl)-4-ethyl,5-n-propyl-cyclohexane. 5.Bicyclo(2.2.1)-2-(isocyanatomethyl)-2-(3-isocyanatopropyl)heptane.